1. Field of the Invention
To release a store such as a bomb, missile or other munition from an aircraft it is commonplace to mount the store on a suspension arrangement including two suspension hooks and, upon release of the suspension hooks positively to eject the store away from the aircraft. This is necessary to ensure that the store falls away from the aircraft and is not held entrained by the airstream against the aircraft.
2. Discussion of Prior Art
There have been many attempts to improve the existing store ejector system and one of the most sophisticated is described in our earlier British patent application no. 8905697.2 which describes a store ejector in which the ejection thrust applied to the store varies as the store moves away from the aircraft. It achieves this by including a variable orifice valve between a source of pressurized fluid such as an ignited pyrotechnic cartridge and a pneumatically operated ram driven by the high pressure fluid. The operating member of the variable orifice valve is connected directly to the ram so that as the ram extends it automatically moves the operating member of the variable orifice valve to vary the degree of throttling of the high pressure fluid. This arrangement is a considerable advance over previous systems where the ejection thrust was solely dependent upon the rate of burning of the pyrotechnic cartridges and any fixed throttles located between them and the rams but, it only operates over the initial movement of the ram and requires the manual fitting of the appropriate variable orifice valve to match the store to be loaded onto the suspension system.
In any store ejector which requires as its source of fluid under pressure the initiation of pyrotechnic cartridges the particular pressures that are obtained vary with the number and power of the cartridges loaded into the breaches and also vary with the individual burning characteristics of each cartridge. Whilst attempts are made to provide cartridges with a reliable and repeatable burning characteristic they do still vary from one to another and from batch to batch with the result that variations in the pressure generated by the individual cartridges gives rise to variations in the ejection of the store.